In U.S. Pat. No. 3,984,350 a method of forming a high activity, low solubles producing, brown catalyst component comprising beta titanium trichloride is taught which has its prime utility in the polymerization of propylene or a propylene dominated alpha-olefin mixture when promoted with an alkylaluminum compound. Such component is a high surface area, large porosity material containing a small amount of one or more organic electron donor compounds. Although the component produces a large polymerization yield of crystalline polymer and a small solubles production compared to all prior art beta titanium trichloride catalyst components, further improvements can be of extreme commercial importance because of the size of yearly world production of such polymers. For example, even a one percent decrease in production of soluble polymer while maintaining or not seriously reducing the crystalline yield could produce savings in the millions of dollars per year range.
Now it has been found that if a material such as an ester, an amine, an organic boron or a coordinating, cyclic hydrocarbon containing at least one double bond, etc., is used in the preparation process prior to use in polymerization, an improved component results which produces substantially decreased polymer solubles at substantially the same crystalline polymer yield.